Peroxydisulfate activation by cerium (IV) oxide-supported palladium (Pd/ CeO2) for bisphenol A oxidation and E. coli inactivation from aquatic matrices

In this study, a series of Pd/CeO2 catalysts were synthesized, characterized, and evaluated for the activation of persulfate and the degradation of the micropollutant, bisphenol A (BPA). The efficiency followed a volcano -type behavior with respect to Pd loading, and the 0.25% wt. Pd/CeO2 exhibited the highest catalytic activity. However, this activity strongly depended on the operating conditions. The system was able to degrade 500 mu g/L BPA in less than 30 min, and the removal was favored at near neutral pH (6.2). Scavenging experiments highlighted the role of superoxide and singlet oxygen, followed by sulfate radicals. The efficiency was found to be stable across several cycles, despite a slight decrease in the first cycle. The removal of BPA decreased with the complexity of the water matrices, showing the need for system optimization under real conditions. Five transformation products were identified using UHPLC/TOF-MS and their ecotoxicity was estimated using ECOSAR. Intriguingly, the system was capable of inactivating 99.99% of 2.4 x 105 CFU/mL E. coli, in less than 210 min making it an appealing alternative technology for the simultaneous inactivation of pathogens and degradation of micropollutants in environmental systems.